Is Dropping a column "CHECK" constraint possible?

Hi Folks ,

can anyone please help?
i have a to drop a check contstraint from a column. eg

tradein_clients=# \d t_a          Table "t_a"  Column   |  Type   | Modifiers
------------+---------+-----------company_id | integer |exp        | text    |imp        | text    |
Check constraints: "$1" (length(imp) > 1)                  "aaaaaq" (length(imp) > 1)

Can i remove to contraints thru ALTER TABLE or similar commands.
I have read the docs for ALTER TABLE but the command described is
not working for me.

=======================================================
ALTER TABLE [ ONLY ] table       DROP CONSTRAINT constraint { RESTRICT | CASCADE }
========================================================

Regards
Mallah.

--
Rajesh Kumar Mallah,
Project Manager (Development)
Infocom Network Limited, New Delhi
phone: +91(11)6152172 (221) (L) ,9811255597 (M)

Visit http://www.trade-india.com ,
India's Leading B2B eMarketplace.